Melanoma is the most serious of the common types of skin cancer. Unlike basal cell carcinomas and squamous cell carcinomas, it can spread rapidly to the lymph system and internal organs. If this happens, melanoma can be fatal. Every day in the United States, someone dies from melanoma approximately once per hour. However, this does not mean that all melanomas are lethal. In fact, the vast majority are not. If melanoma is detected early and treated properly, the cure rate is about 95%.
Melanoma accounts for about 4 percent of all skin cancers. Thus, it is much less common than basal cell carcinoma and squamous cell carcinoma, but more common than any of the rare types of skin cancer, such as Kaposi sarcoma or Merkel cell carcinoma.
Melanoma begins in the melanocytes, which are the cells in the epidermis (the upper layer of the skin) that give skin its color. Melanoma may develop in a mole that is already present on the skin or may look like a new mole. It is important for people to know what their moles look like, so that they will be aware of changes in moles or the appearance of new moles. Both new and changing moles should be examined by a doctor.
Because the melanocytes produce the dark pigment melanin, melanomas are usually brown or black. However, it is possible for melanomas to have no special pigmentation and be the same color as the surrounding skin.
Melanomas can occur anywhere on the body. In men, they occur most often on the chest, stomach, or back. In women, they occur most often on the lower parts of the legs. The face and neck are other common sites for melanoma in both sexes. All of these are parts of the body that are at least sometimes not covered by clothing and that therefore may be exposed to the sun.